Merge "Add Intel PMEM driver specification"
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Zuul
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This work is licensed under a Creative Commons Attribution 3.0 Unported
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License.
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http://creativecommons.org/licenses/by/3.0/legalcode
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=================================
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Cyborg Intel PMEM Driver Proposal
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=================================
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https://blueprints.launchpad.net/openstack-cyborg/+spec/add-pmem-driver
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This spec proposes to provide the initial design for Cyborg's Intel PMEM
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driver.
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Problem description
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===================
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This spec will add Intel PMEM driver for Cyborg to manage specific Intel
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PMEM devices.
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PMEM devices can be used as a large pool of low latency high bandwidth memory
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where they could store data for computation. This can improve the performance
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of the instance.
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PMEM must be partitioned into PMEM namespaces [1]_ for applications to use.
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This vPMEM feature only uses PMEM namespaces in devdax mode as QEMU vPMEM
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backends [2]_. If you want to dive into related notions, the document NVDIMM
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Linux kernel document [3]_ is recommended.
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Starting in the 20.0.0 (Train) release, the virtual persistent memory (vPMEM)
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feature in Nova allows a deployment using the libvirt compute driver to provide
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vPMEMs for instances using physical persistent memory (PMEM) that can provide
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virtual devices [4]_.
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Use Cases
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---------
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* As an operator, I would like to use Cyborg agent managing PMEM resource
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and checking periodically, the Cyborg Intel PMEM driver should provide
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``discover()`` function to enumerate the list of the Intel PMEM devices,
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and report the details of all available Intel PMEM accelerators on the
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host, such as PID(Product id), VID(Vendor id), Device ID.
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* As a user, I would like to boot up a VM with Intel PMEM Device attached in
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order to accelerate compute ability. Cyborg should be able to manage this
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kind of acceleration resources and assign it to the VM(binding).
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Proposed change
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===============
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1. In general, the goal is to develop a Intel PMEM Device driver that supports
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discover interfaces for Intel PMEM accelerator framework. The driver should
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include the ``discover()`` function. This function works excuting "ndctl list"
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command that reports devices' raw info sample as following::
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[
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{
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"vendor": "8086",
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"product": "ns200_0",
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"device": "dax0.0"
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}
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]
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2. Generate Cyborg specific driver objects and resource provider modeling
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for the PMEM device. Below is the objects to describe a PMEM devices which
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complies with the Cyborg database mode and Placement data model.
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::
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Hardware Driver objects Placement data model
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1 PMEM 1 device |
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| 1 deployable ---> resource_provider
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| | ---> parent resource_provider: compute node
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n Namespace n attach_handle ---> inventories(total:n)
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3. Need add the "enable_driver=intel_pmem_driver" in the Cyborg Agent
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configure file.
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4. Need add the "pmem_namespaces=$LABEL:$NSNAME|$NSNAME,$LABEL:$NSNAME|$NSNAME"
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in the Cyborg Agent configure file as:
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"pmem_namespaces = 6GB:ns0|ns1|ns2,LARGE:ns3"
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5. Resource class follows standard resources classes as:
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"CUSTOM_PMEM_NAMESPACE_$LABEL"
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6. Traits follows the placement custom trait format. In the Cyborg driver, it
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will report two traits for PMEM accelerator using the format below:
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trait1:"CUSTOM_PMEM_NAMESPACE_$LABEL1"
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trait2:"CUSTOM_PMEM_NAMESPACE_$LABEL2"
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7. Before cyborg discover the namespaces, they should be created. How to create
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the namespce can reference [5]_ and [6]_.
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Alternatives
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------------
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None
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Data model impact
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-----------------
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Need add new type such as PMEM in devices and attach_handle tables.
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REST API impact
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---------------
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None.
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Security impact
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---------------
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None
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Notifications impact
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--------------------
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None
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Other end user impact
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---------------------
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User can manage Intel PMEM Device by Cyborg Intel PMEM driver. Such as list
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of the Intel PMEM devices, report the details of all available Intel PMEM
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accelerators on the host, binding with Intel PMEM and so on.
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Performance Impact
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------------------
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None
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Other deployer impact
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---------------------
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None.
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Developer impact
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----------------
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None
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Implementation
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==============
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Assignee(s)
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-----------
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Primary assignee:
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qiujunting(qiujunting@inspur.com)
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Work Items
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----------
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* Implement Intel PMEM driver in Cyborg
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* Add related test cases.
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Dependencies
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============
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None
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Testing
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========
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* Unit tests will be added to test this driver.
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Documentation Impact
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====================
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Document Intel PMEM driver in Cyborg project.
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Add test report in cyborg wiki.
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References
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==========
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.. [1] https://pmem.io/ndctl/ndctl-create-namespace.html
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.. [2] https://github.com/qemu/qemu/blob/19b599f7664b2ebfd0f405fb79c14dd241557452/docs/nvdimm.txt#L145
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.. [3] https://www.kernel.org/doc/Documentation/nvdimm/nvdimm.txt
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.. [4] https://docs.openstack.org/nova/latest/admin/virtual-persistent-memory.html
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.. [5] https://docs.openstack.org/nova/latest/admin/virtual-persistent-memory.html#configure-pmem-namespaces-compute
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.. [6] https://pmem.io/ndctl/ndctl-create-namespace.html
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History
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=======
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.. list-table:: Revisions
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:header-rows: 1
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* - Release
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- Description
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* - Yoga
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- Introduced
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